Taiwanese Patent Publication No. 263510 discloses 1,8-benzo[b]naphthyridine derivative in which three aromatic rings are fused in a linear manner. The derivative is useful as an antimicrobial agent.
It is disclosed in J. Org. Chem., 1990, 55, 6140-6147 a 1H-2,3-dihydro-1,9-diazaphenalene derivative of the following formula:

where Ar represents phenyl, 4-methylphenyl, 4-methoxyphenyl, 4-chlorophenyl or 4-fluorophenyl, and R represents hydrogen or benzyl. As shown in the above formula, not all of three fused cyclic moieties are aryl rings.
There is a need in the art for a 1,9-diazaphenalene derivative which contains a plurality of fused aryl rings and which is highly substituted.